Communication is the key here. If you are calling in a police action and getting involved or even considering it, a cell phone is a must. Calling in your observations is one thing, but how you are dressed and if you are armed are also key points here. One thing that the responding officers want to know is who the bad guys are and who are the good guys. We do not have white hats to wear off-duty for easy identification.
We are not doing the fashion column here, so keep your description of yourself simple with colors. For me, my description would be white guy, mid 50s, gray hair, black golf shirt, blue jeans, and sneakers. They do not need to know the brands of jeans and sneakers. We are cops, not the fashion police.
For calling in on the cell phone, know a few tidbits. Are you in or out of jurisdiction? If you are traveling out of state, most state patrol has a special number instead of 911. For instance, Georgia is *GSP. If you live out of your primary jurisdiction, do you have a precinct or local station number stored on your phone that you can easily dial?
When you call in, use plain speak! Your codes and signals probably mean nothing to them. Another problem is that you may not know where the heck you are. Even on vacation, do not ride around oblivious to the world... pay attention to streets, locations, highways, exits, or something. Do not rely on blind luck; stay aware of your surroundings.
Keep Your Cool